Thousands of fish have been rescued in Surrey after a five-kilometre section of the River Mole disappeared into a sinkhole, environmental officials confirmed.
Environment Agency workers used electrofishing equipment to stun the fish and collect them in nets before transferring them to deeper, safer waters further upstream.
Dave Webb from the Environment Agency said the river flows through chalk rocks and vanished into a karst sinkhole, leaving the riverbed completely dry. He noted that water in the section would normally reach waist height on officers.
Webb added that fish can survive in isolated pools for some time during normal summer conditions. However, oxygen levels drop over time as the pools shrink, and extremely high temperatures worsen the situation further.
Extreme heat warning in place
The rescue reported by ITV News came as a rare amber warning for extreme heat came into force across large parts of England, with the United Kingdom potentially facing its hottest day of the year. Temperatures could reach 38 degrees Celsius in some regions during the fifth heatwave of the season, which appears on track to break the heat record set last year.
The amber weather warning issued by the Met Office extends from London to Sheffield. It covers parts of the South East, East Midlands, East Anglia, West Midlands, and South Yorkshire.
British Met Office forecaster Alex Burkill said temperatures in the warning areas could peak at 36, 37, or possibly 38 degrees Celsius. He warned that such high temperatures can negatively affect roads, railway tracks, and other infrastructure not built for extreme heat, while also posing risks to public health.
Burkill added that if temperatures exceed 38 degrees Celsius, it could mark the hottest day of the year so far. Temperatures above 38.5 degrees Celsius would set a record for the hottest August day ever recorded in the UK, although he noted that outcome remains quite unlikely.
Global heatwave impacts
Extreme summer weather has also caused severe water shortages across continental Europe, Ukrainian news agency UNIAN reported. Authorities in Switzerland banned residents from filling swimming pools and watering lawns as water levels in numerous rivers and lakes dropped to historic lows.
In Italy, visitors and residents in Rome have sought shelter from the heat underground. Local guidebooks recommend taking refuge inside historic churches during peak daytime temperatures to stay cool.
River Mole and conservation methods
The River Mole is a tributary of the River Thames that flows through Surrey and West Sussex in south-east England. Chalk bedrock beneath sections of the river frequently absorbs surface water through swallow holes during prolonged dry spells. Electrofishing is a standard conservation method that uses mild electric currents to temporarily immobilise fish so wildlife teams can safely relocate them.
